Quaternary ammonium salts of alkanolamines esterified with an average of two fatty acid moieties per molecule, commonly referred to as ester quats, have found broad use as fabric softeners. One problem with the use of these compounds is that they are typically difficult to disperse in water or aqueous solutions at temperatures below about 40° C. This can make the preparation of formulations more difficult and expensive.
One attempt to address problems of ester quat dispersibility was made by Gallotti et al. (WO 2008/003454). This reference discloses concentrated ester quat compositions that can be used in fabric softeners and which are especially suitable for use in low temperature processes. The compositions contain (a) an ester quat compound, specifically di(ethyl ester) dimethylammonium chloride (DEEDMAC) type (b) an organic solvent, (c) water, and (d) stabilizers.
U.S. Pat. No. 5,830,845 discloses concentrated aqueous fabric softening compositions that can be made at ambient temperature. The actives described have fatty acid alkyl moieties with iodine values higher than 80. In general compositions have a polyunsaturated content of more than 10%, and a monoester quat content below 20% by weight.
EP 1 584 674 A1 discloses ester quat concentrates which it suggests can be used for the production of fabric softeners at lower temps. The compositions contain: (a) an ester quat compound, (b) an organic solvent, (c) water, and (d) a pH modifier. The reference suggests that water is essential for dispersibility at low temperature.
WO 97/42279 discloses triethanolamine ester quat concentrates to be used for the production of fabric softeners. The compositions comprise greater than 55% by weight diester quat and less than 25% by weight triester quat, based on the total amount of quaternary ammonium salts. Dispersing these ester quat concentrates in water to make an aqueous fabric softener requires preheating water to 45-60° C.
Despite the efforts that have been made, there is still a need for improved ester quat compositions that can be easily dispersed in water or aqueous solutions at low temperatures and that maintain the ability to act effectively as fabric softeners.